Who called from 2132131232

Wondering why I pick up my phone and answer with hello they hang up

Continual calls but only hangs up when I answer

This was a scam caller who said they were from internet security service and they were getting suspicious messages fro my computer.

I have received two calls from this number.  They do not leave a message.  Would like to stop them from calling.

Keep getting calls from that number 3 til 4 times a day. I said hello and they hang up . Be careful    I stop answering when I see the number 2132131232.